More particularly, the invention relates to a system for packaging and applying a product, comprising:                a container intended for containing said product and having a neck and a bottom, the neck extending along a longitudinal axis;        a product application assembly including a closing element adapted for closing the container, and a product applicator secured to said closing element and intended for insertion into said container in order to be loaded with the product to be applied;        a retaining device adapted for retaining said application assembly on said container, and mounted to be movable between an operative configuration in which the application assembly is retained on the container and an inoperative configuration in which the application assembly can be removed from the container;        a resilient element provided so as to adopt a stressed configuration when the retaining device is in the operative configuration, the transition to the inoperative configuration of the retaining device causing the expansion of said resilient element.        
Document EP1800561A1 discloses an example of such a system where the application assembly has a closing cap and an application shaft slidably mounted inside said cap and resiliently biased to an extended position in which the shaft protrudes the furthest from said cap. In the storage position, the shaft of the application assembly, resting on the neck of the container, is retracted inside the cap which compresses an internal spring, the cap being held in this position via the complementary retaining means provided on the cap and the container. These retaining means comprise locking balls arranged at said cap and intended to enter into a complementary groove provided on the container neck, and a sleeve associated with said cap and adapted to keep said locking balls within said groove in the operative configuration of said retaining means, thereby preventing removal of said application assembly from said container. When a user wishes to use the application assembly, the user grasps the container and lifts the sleeve relative to the cap so as to allow the balls to disengage relative to the container neck. The cap is then no longer retained on the container in the axial direction, which causes the expansion of the inner spring and drives the cap away from the shaft and the container, allowing the removal of the application assembly from the container.
Thus, when the user acts to disable the retaining means, only the cap of the applicator is moved along a specific axial stroke away from the container under the effect of the relaxing inner spring, the shaft remaining inside the container, resting on its neck.
This cap then constitutes a gripping and manipulation element that the user grasps in order to withdraw the shaft from the container and apply the product to a surface. Once withdrawn from the container, the shaft is only held in its extended position relative to the cap by the resilient urging of the internal spring. When a user wishes to apply the product loaded on the applicator shaft to a surface while gripping the cap, this cap may be pushed over the shaft against the elastic force of the spring, which can interfere with proper application, especially in terms of precision and uniformity of the applied layer of product. Such internal mobility of the application assembly additionally harms the user's overall perception of the quality of the product packaging and application system.